Buoyant aircraft with hydroskis



' y 1953 J. R. DAWSON, SR 6,

BUOYANT AIRCRAFT WITH HYDROSKI'S- Filed May 29, 1951 s .s'het's snet- 1 IN VEN TOR.

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I 2,646,235 BUOYANT AIRCRAFT WITH John R. Dawson, Sr., Hampton, Va. I v Application. May va9, 1951,5eflal-Nu. 228,961 ice-rm. i (01. 244-105) Granted under This invention relates to aircraft, including amphibian aircraft which oan-take-o'fi' from and land on water and other surfaces". Airplanes constructed in accordance: with the present im-" provementsmay descend to contact with deep or shallow water and subsequently be broughttorest in water or on a beach. Theymay land and take-01f from other surfaces-such as ice-and snow. More-particularly invention is directed to airplanes which may be" either jet or. propeller powered and which are equipped with depending hydroskis. The hydroskis may be'of solid construction such as solid aluminum and they provide dynamic lift when running submerged water or planing on the surface of the water for supportingan airplane iduring take-cit and landings During normal night the hydroslcis may be retracted and become a portion of the surface of the fuselage or wings; The present concept admits of considerable variation inthetformof the airplane fuselage and wings forming the gbody of I the plane and in the form of the hydroskis.

Prior to the present improvements, flying boats and seaplanes having hulls: or floats to provide buoyancy, to hydrostatically support an airplane,-

were known. Hydrof-oils'have been used as a sub-- stitute for the planing bottom'on floats. Hydrofoils, however, are-of substantial width and have anaspect ratio (the square oithe span divided wise so that runningsubmerged in water! theyde- 'velop hydrodynamic-lift by suction on thetupper surface in combination with positive pressure on the lower surface. Snow skisthave loeen useduas an attachment for landing and takmgofi on snow and ice. They are not, however, designed; :for' use on water. Hydroskismayhavea plan are'a approximately one-third'U/ at of conventional snowsk-is. I I3 3 The above and all other landing: gear devices of which I am aware differ materially from themesent concept both .instructure and function.

According. to the invention there isprovi'ded an airplane having a fuselage and wingsforming v the body of the plane. The lower portionsofthelaody is "water tight and buoyant to provide hydrostatic or hydrodynamic supportingaccording to .requirements of the particular design Extending downwardly, and preferably but-not necessarily retractably mounted, are one or more: supports for a hydroski. The term hydro'ski; as 'used-in the present description and fClE-llI-IS', may he idefi'ned-as a member which is joinedtoan-airplane and'wh-ich provides hydrodynamiclift tormeaiw Title 35, U. s.v 19523 sec. 266.)"

plane whilerunning up er the water or planing upon the water. Unlike the hydrofoil, it has an aspect-ratido fl-ess-than unity. a r Y The hydrosk idiifers-froma seaplane float that it provides no material buoyancy. Thepresent invention contemplates the total immersion of'the relatively small: hydroski and the: use of streamlined struts to which the hydroski rigidly secured. The streamlining of the struts is to in sure that "resistance to movement throughwater will be'minimized. vThe struts may retraet pivotahly or axially .so that both the hydroskl and strut :or the -.hydroski will fit: into the :body portion in a manner to provide" asmooth' body surface diiringlnormazl flight. v

incidental todesign and that small size and other factors herein set forth are controlling.

As previously mentioned the aspect ratio of a hydroskii is less than unity; In fact there are a number of successful designs having aspect ratios from about .1 or less to" 15 This range includes many configurations which can knife through water' intaking oh" and landing operations with a minimum of resistance to forward motion. This is important because in take-off from water the greatestresistance' to the propelling thrust may occur just'prior'to thehod'y portion of the plane 40 "leaving the water although this may be varied within reasonable limits; For example, a typical take-off of a jetfplaneweighing l3,500"pounds and constructed according'to the inventionwill inelude the plane moving through water with the hydroskis and-struts submerged, and the watertight body portion and hydroskisv providing hydrodynamic buoyancy. At approximately 38 to 40 miles per hour the tbodlll vporti-on leaves: the water- 'and the h-ydrosk is move on and along the surface until at about 148 milesper hour the plane'wflltake off from the water and the hydrosk-is may retracted for normal high-speed: flight. 7 a l 1 An object 01 inventibn is to aprovide an aircraft having a body with awater-tight lower: portion" 3 2nd one or more hydroskis extending below said ody.

Another object is to provide a landing gear that does not impair the low drag qualities of an air plane and permits landing on water with less impact load on the airplane body;

Another object is to provide a landing gear which is smaller than hulls and floats and which is strong to withstand high speed water loads with the result that lighter airplane structure may be constructed.

Another object is to provide a landing gear which does not require very long concrete runways but which may use land or water and combinations of each for landing and take-off operations. V

Another object is to provide a seaplane equipped with hydroskis extending below.

Referring to the drawings, Figs. 1, 2, and 3 schematically show an aircraft having a fuselage ID and wings I I forming the body portion of a jet plane. A set of hydroskis l2, l3, I4, and IE or i2, [3, M, and I5 are joined to the plane by streamlined struts l1, l8, l9, and or 2|. The

struts are preferably retractable so as to position move and which the struts seal when in place.

Another object is to provide aircraft provided of resistance to forward motion of the aircraft while the hydroskis are submerged and which will provide support to the aircraft when the hydroskis are moving on the surface of the water.

Another object is to provide an aircraft equipped with hydroskis, the bottom surface of which provides the greater portion of the lift when running submerged.

Another object is to provide an aircraft equipped with hydroskis which are tapered at their trailing edges to reduce bounce or pitch and thus increase the landing stability on water.

Another object is to provide an aircraft equipped with hydroskis for landing and take-off from water, ice, snow and other surfaces.

These and other objects of invention-will be manifest from a consideration of the following description claims and drawings in'whichz.

Fig. 1 is a side elevational view ofan aircraft with retractable hydroskis positioned in the wings, as well as centrally of the fuselage. One additional hydroski is positioned either in the front or the rear portion of the fuselage. The

front hydroski and support are shown in dotted K lines.

Fig. 2 is a bottom plan View of the aircraft of Fig. 1.

Fig. 3 is a. front view of the structure of Fig. 1 with the front hydroski omitted from the view.

Figs. 4,5, and 6 are similar to Figs. 1, 2, and 3 respectively, but show a different arrangement of hydroskis and supports. As in Figs. 1, 2, and 3 either the front or rear hydroski may be eliminated in accordance with requirements.

Figs. '7 and 8 are a bottom plan and front view respectively of a modification in which the wings are secured in a lower portion of the fuselage and slope downwardly so that the wing tips may provide a degree of buoyancy.

Fig. 9 is a schematic view, partly in section, of a wing and one of many types of retracting devices which may be used.

Fig. 10 shows a modified position of joinder for the strut and hydroski of Fig. 9.

Fig. 11 is a schematic view of a vertical hydroski retracting means which is used in the fuselage.

Figs. 12 and 13 are sections of a hydroski on the lines l2-l2, l3l3 of .Fig. 11.

The wings are set sufficiently high so that they remain above the water during landing and takeoff operations. They contain a pivotal support for the struts. I8, [9.

The main hydroski I2 is positioned below the center of gravity of the plane; the tail hydroski I5 is placed well aft of the center of gravity and the two side hydroskis l3 and M are on the wings and outboard of the center line of the airplane. With this arrangement, i. e. excluding hydroski IS, the airplane rides on the main hydroski i2 and tail hydroski i5. When the hydroskis reach the planing condition and at higher speeds the airplane can be made to ride on the main hydroski alone by proper setting of the conventional controls. The side hydroskis provide lateral stability at low planing speeds where the aerodynamic control is insufficient to maintain lateral stability. It will be noticed that the main hydroski of the embodiments of Fig. l is lower than the others except when a front hydroslzi is used. The latter may be slightly inclined to facilitate the approach and movement out of water onto a beach.

Figs. 4, 5, and 6 differ from Figs. 1. 2, and 3 in that there are no supports for hydroskis in the wings. Instead, two hydroskis 25, 25 are rigidly secured to streamlined supports 21, 28 both of which are retractable into the fuselage on opposite sides of the center line of the plane near the center of gravity. As suggested above either the front or rear hydroski 29hr SI and its support 30 or 32 may be dispensed with in accordance with requirements.

Figs. '7 and 8 illustrate a modification having only a single hydroski 35 below the center of gravity of the plane. Its streamlined retractable support 36 is rigidly secured to the hydroski 35. In this modification the wings I! slope downwardly toward their tip as shown and are set low with respect to the fuselage I0. When the plane is in deep water the wing-tip portions will be immersed so as to supply a portion of the buoyancy with the fuselage.

Fig. 9 shows a recessed wine partly in section. A shaft spans one end of the recess and projects into the inside of the wing. Slotted lever 52, inside the wing and fixed to shaft 50, is connected to piston rod 53 of hydraulic control 54 for the extension and retraction of strut 5| and its rigidly secured hydroski 55. The hydraulic control includes a two way valve 56 for controlling the fluid within the cylinder and the movement of the piston rod 53 in a known manner. Any convenient way. of moving the lever 52 may be substituted as the form of actuating means is not critical.

The hydroski 55 may, if desired, be secured to strut 5| as shown in Fig. 10, although the central securing of Fig. 9 is preferred. It will be observed that the structure of Fig. 10 admits of this construction the strut 60 may act as a piston rod in cylinder 6|. The two-way valve 63 and positioned below the center of gravity. It will be understood that it is not necessary that the point of securing be directly under the center a of gravity. Some part of the main hydroski is conventional accessary equipment controls the position of the'hydroski 64.

Hydroskis 55' and 64 are concave transversely top and bottom and have line cross sections. at

' their ends as shown in Fig. 13. Fig. 12 represents a near central cross section. The hydroski constructions are preferably those which'provide more lift onthe bottom and tend to minimize any effect of loss of lift from the top surface when the hydroski moves upwardly from submerged position during take-off. A flat bottom, will pro-' duce more lift than that shown in Fig. 12 but the latter will fit into the fuselage better.

The hydroskis shown in Figs. 1 thru 8 are convex on the top and bottom'and tapered as shown. Those below the center of gravity are preferably generally parallel to the axis of flight of the aircraft.

The leading edge, Fig. 12, is preferably sharp and preferably is notturned up especially for use in water. A construction having a flat forward top portion and an under surface curving rearwardly and downward is practical, however. Turned down lateral edges are excellent for splash control. It may be formed from any light, strong metal or laminated wood and the like which can maintain its position relative to the supporting struts during operation. The sharp leading edge enables the hydroski to knife through waves of 2 or more feet high during a water landing operation without ill effect. The plan form design may vary considerably and may be rectangular, triangular or tapered at the trailing end as shownin Fig. 2 for example. The triangular formmay have a short side of the triangle as the leading edge with'the other sides tapered. to reduce bounce and pitch and cavitation in a manner similar to the plan form shown in Fig. 2. The mountings for the struts may of courseinclude some shock cushioning structure below the center of gravity of the plane.

It is not desired that the scope of the invention be limited to the described embodiments but rather only by the scope of the attached claims and their legal equivalents.

The, invention described herein may be manufacturedor used by or for the Government of the United States ofAmerica for governmental purposes without the payment of any royalties thereon' or therefor.

I claim:

- 1. An aircraft having a body which includes a r I fuselage and Wings, said body having a watertight lower portion which will provide sufiicient buoyancy to support the aircraft in deep water, a hydroski supported by said aircraft body and having anaspect ratio less than unity, a streamlined strut connected to the hydroski and extending upwardly to the body, said strut having-a width less than the span of the hydroski, means for retracting the hydroski into the body of the aircraft, the hydroski and body forming an approximately continuous'surface when the hydroski is retracted, said hydroski being inclined upwardly over its length and toward its leading edge, and the trailing end of the hydroski being tapered rearwardly.

2. The combination of claim 1 further defined in that the hydroski has no inherent or hydroduring movement while submerged or on the or characteristic if movement is confined to narrow limits but the rigid construction is preferred. If more than one strut is used it is preferred that they be aligned to reduce resistance.

The terms hydrostatic and hydrodynamic lift or buoyancy as used herein refer to lift or support when the aircraft is at rest in or is movinga of attack as is normal at take-off, the hydroskis, even though rigid, will automatically assume a position giving additional. assurance against bounce or pitch.

The main hydroskis have been described as surface of water.

3. An aircraft having a body which includes a fuselage and wings,'said body having a watertight lower portion which will provide sufficient buoyancy to supportthe aircraft in deep water, a hydroski spaced from and positioned below the fuselage near the center of gravity of the aircraft and having an aspect ratio less than unity, streamlined means connecting said hydroski to said fuselage, and another hydroski positioned below and on each side of the center of gravity of the aircraft.

4. The combination defined in claim 3 further defined in that the hydroskiis retractable and that the bottom of the hydroski and the-fuselage form asmooth surface when the hydroski is in fully retracted position. V

' JOHN R. DAWSON, SR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,165,770 Gallaudet Dec. 28, 1915 1,776,700 Pegna Sept. 23, 1930 1,815,303 Kloen July 21, 1931 2,131,528 Soyer Sept. 27, 1938 FOREIGN PATENTS Number Country Date 354,841 Germany June 16, 1922 587,317 Great Britain Apr. 22, 1947 

